1. Field of the Invention
The present invention relates to a ground fault detection device which, for example, is carried upon a vehicle or the like.
Priority is claimed on Japanese Patent Application No. 2003-123641, filed Apr. 28, 2003, the content of which is incorporated herein by reference.
2. Description of Related Art
Conventionally, there is, for example, a known method of ground fault detection, in which the presence or absence of occurrence of a ground fault at an appropriate position of a direct current circuit which is equipped with a high voltage direct current power source is detected by selectively switchover connecting a current detector or a voltage detector for ground fault detection to the anode side and the cathode side of the direct current circuit (for example, Japanese Patent Application Unexamined Publication No. 4-12616).
Furthermore, in this type of ground fault detection method, there is a known detection method, in which the power source voltage of the high voltage direct current power source is detected, and variation of the detection result of the current detector or of the voltage detector for ground fault detection due to variation of the power source voltage is compensated according to this detected value of the power source voltage (for example, Japanese Patent No. 2838462).
However, in the above described conventional ground fault detection method, there have been the drawbacks that it is necessary to provide a voltage detection section for detecting the power source voltage of the high voltage direct current power source, and also that a structure for compensating for variation of the detection results of the current detector or the voltage detector for ground fault detection, based upon the detection results of this voltage detection section, has been necessary, so that, as a whole, the structure of the device has become complicated.
The present invention has been made in the light of the above described problems, and an object thereof is to provide a ground fault detection device which can detect the presence or the absence of the occurrence of a ground fault at high accuracy, while avoiding excessive complication of the structure of the device.